[Risks and side effects of autologous transfusion]

Several versions of autologous transfusion are becoming increasingly popular. This review deals with their risks and side effects, which are still insufficiently documented. Basically, a number of preexisting conditions amounting to a subnormal performance and reserve capacity of several organ systems contraindicates preoperative donations, but 'critical' values of relevant parameters are still under debate. Since a preoperative deposit implies that the same individual donates several units within a few weeks, reaction rates must be related to the number of donors rather than that of donations. Viewed this way, the risk of--usually cardiocirculatory and sometimes serious--incidents is two times higher in autologous than in homologous donors. The reduction of oxygen transport capacity is a matter of concern. In order to avoid a mixed-venous p02 less than 35 mm Hg, which indicates an impending oxygen deficit, all 'non-hemoglobin' factors impacting on tissue oxygen supply must be normal even with 10 g/dl of hemoglobin; lower Hb values are undesirable. The use of erythropoietin to boost the preoperative harvest of red cells may not, by itself, be risky, but the accelerated pace of donations obviously is. The quality of cellular blood products prepared by intraoperative machine autotransfusion still leaves much to be desired. The suspicion that adenine and, especially, fibrinogen degradation products may be immunosuppressive, raises questions about the liberal use of autologous fresh frozen plasma. Bacterial contamination of reservoirs and the presence of tumor cells as well as fat droplets from bone marrow cannot be dismissed as being unimportant. Suction devices activate coagulation and fibrinolysis. Altogether, the risks of autologous transfusions, though different from those of homologous blood, require further efforts aimed at their reduction.